Among fellow troops, that can mean facing ethnic taunts, awkward questions about spiritual practices and a structure that is not set up to accommodate their worship. Among Muslims, the questions can be more profound: How can a Muslim participate in killing other Muslims in such places as Iraq and Afghanistan?

Just 3,557 members of the 1.4 million-member U.S. armed forces describe themselves as Muslim, and followers of Islam said the military is just starting to accommodate them by recruiting Muslim chaplains, creating Muslim prayer spaces and educating other troops about Islam.

Active and retired Muslim service members recalled difficulties concerning their religion but said they cannot relate to the extreme isolation and harassment described by Maj. Nidal M. Hasan, the suspect in last week's Fort Hood slayings. They also said they hope the killings do not roll back the progress they have seen.

Joshua Salaam, 36, said superiors told him when he joined the Air Force that he could not take time for regular prayer. He remembered being warned at a briefing for a posting in Qatar not to go to mosques because of potential violence. Once he arrived, other service members told him that Muslims there wore baggy clothes because Islam calls for them to avoid public bathrooms.

"They are the enemy," is how Muslims were sometimes characterized, he said.

But Salaam said he received many awards in the Air Force. He wore his "kufi" -- a rounded cap popular with some African American Muslims--on base and came to like being a "cultural translator" for both sides.

"As a Muslim growing up in America, we've been doing that our whole lives anyway," he said.

Interviews with Muslims revealed a range of experiences. Some choose to keep their faith private; others seek out superiors and chaplains who can help them worship even on duty. Some blamed other Muslims for not working to fit into military culture.

Sgt. Fahad Kamal, 26, attended the same Texas mosque as Hasan, the Islamic Center of Killeen, and reenlisted at Fort Hood after serving as a combat medic in Afghanistan. He said he experienced the rare insult from other soldiers about his religion and described one occasion during basic training when someone called him a "terrorist."

"I knew he was just kidding, but the drill sergeant overheard him. He made him apologize in front of the entire company" and do push-ups. "I felt guilty, because I knew he was just joking. But I was also happy to see how seriously they took it."

Kamal, whose family left Pakistan for Texas when he was a boy, said he didn't find the Army anti-Muslim. "We've got a president whose middle name is Hussein. He comes from a Muslim background. Our soldiers are from every race and culture," he said.

Gen. George W. Casey Jr., the Army chief of staff, said this weekend that he was worried about a possible backlash against enlisted Muslims. "It would be a shame, as great a tragedy as this was, it would be a shame if our diversity became a casualty as well," he told CNN.

In a broadcast Monday night, Virginia Beach religious broadcaster Pat Robertson said the military overlooked Hasan's troubles because of a politically correct refusal to see Islam for what it is. "Islam is a violent -- I was going to say religion -- but it's not a religion. It's a political system. It's a violent political system bent on the overthrow of governments of the world and world domination."

One of the best-known allegations of anti-Muslim harassment in the military involved James Yee, a former Muslim Army chaplain at Guantanamo Bay, Cuba, who was accused of spying and held in solitary confinement in 2003. The charges were dropped, and Yee wrote a book contending that they were a result of anti-Muslim sentiment among intelligence officials at the military prison.

An Army spokesman said complaints of religious discrimination are rare: 50 across the entire Defense Department in the past three years. But the Military Religious Freedom Foundation, which works for religious pluralism in the military, said it had received 16 complaints since Thursday from enlisted Muslims.

Saleem Abdul-Mateen, a Washington native who was in aviation electronics in the Navy from 1975 to 1995 and is a national leader of a veterans group, said he straddles two worlds. "Today, a [Muslim] brother said to me, 'You know, if we're about peace, why are we fighting another country?' And that's valid. But you have to support the country when it's right and when it's wrong," Abdul-Mateen said.

Doug Burpee, who took the call name "hajji" as a helicopter pilot, said he "never had a problem in 26 years." Although he loves to engage in academic discussions about religion, he said, he kept his prayer invisible and thinks that Muslim service members, like others, have to compromise to fit into military life.

"There are Muslims who stop in their footprints to pray, and those people might have a problem," he said. "But if you're going to join -- join. If Muslims don't fit in, it's their fault."

Shareda Hosein, who is a Muslim chaplain at Tufts University and a lieutenant colonel in the Army Reserve, said being a Muslim is easier in the military in some ways than in general society because of the rules governing behavior. That said, she described a double existence of a sort.

"When I'm in uniform, I feel totally relaxed. I look like every other person. I get thank-yous at the supermarket, the gas station. But when I'm in civilian clothes, my hijab, I get scrutiny. Sometimes looks and stares speak loudly. Little do they know who I am."

Staff writer William Booth contributed to this report from San Antonio.